Oil gauge fitting



FIG. 1 is a perspective view of an oil gauge fitting showing my new design;

FIG. 2 is a front elevational view of the oil gauge fitting of FIG. 1;

FIG. 3 is a side view taken from the right of FIG. 2;

FIG. 4 is a rear elevation view; and,

FIG. 5 is a side view taken from the left of FIG. 4. 

The ornamental design for an oil gauge fitting, as shown. 